First of All™, why would it even enter your mind that the existence of mixed martial arts would have anything to do with the popularity of professional wrestling?
Second of all, you're still missing the point, and the question still stands: why does anybody like anything? Some people like to go to the theatre; in fact, some people have seen the same show on Broadway over a dozen times. Do you waste time wondering why they like that? Why do some people like anime? Why do some people like sitcoms with laugh tracks? Why do some people like "mock-umentary"-style sitcoms? Why do some people like reality television? Why do some people like "talent" shows, like The Voice, and Dancing With the Stars? Why do some people like cheesy sci-fi shows?
Surely you don't expect me to believe that you, literally, like everything that comes on TV except for wrestling? So, out of all the different things that people like that you don't like, why do you single that out? What is it about the existence of wrestling that offends your sensibilities, but Keeping With the Kardashians is cool?